BOTANICAL IDENTIFICATION AND GENETIC DIVERSITY IN MELONS FROM FAMILY FARMING IN THE STATE OF MARANHÃO

Abstract

The aim of this work was to perform botanical identification and to estimate genetic diversity in two sequential inbred generations (progenies S1 and S2) of melon accessions from traditional agriculture in the state of Maranhão, in order to generate useful information for commercial melon breeding. Two field experiments were carried out in a completely randomized block, using four replicates of 15 accessions from a first selfing cycle in 2013, and three replicates of 25 subaccessions (generation S2) in 2014. Flower and fruit descriptors were measured to obtain quantitative and qualitative data, in addition to a systematized photographic documentation of fruit for visually comparing the progenies S1 and S2. Distance matrices for quantitative and qualitative data were obtained and used to perform a joint analysis and UPGMA method. Large genetic diversity was found in the accessions analysed, since the presence of melon progenies was observed in the Cucumis melo ssp. agrestis, with its botanical varieties momordica and conomom, and of the Cucumis melo ssp. melo, with the botanical varieties cantalupensis and chandalak. Divergence analysis showed the formation of three groups in generation S1 and four groups in S2. However, the groups were not separated either by subspecies or by botanical variety. Thus, in addition to the large genetic diversity among and within melon accessions from family farming in the state of Maranhão, the progenies presented a large introgression of traits of the different subspecies and their botanical varieties due to the reproductive system and seed management of these species.